Frustum embedded fabricated composite protective structure

ABSTRACT

A frustum embedded fabricated composite protective structure is provided, including a restraint frame, a back plate, an infill block and a buffer block. The restraint frame is provided with a plurality of mounting holes matching with the shape of the infill block, the restraint frame is arranged on the back plate, the infill block is in a frustum shape. The buffer block and the infill block are installed in the mounting hole of the restraint frame, the buffer block is arranged on the smaller end of the infill block, and the infill block is wedged into the mounting hole of the restraint frame through a wedge surface mating, . Because this protective structure is assembled by multiple restraint frames and infill blocks, under the prestress restraint of partition blocks, the damage range after penetration or explosion will be significantly reduced, and it can withstand multiple blows.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2022/074353 with a filling date of Jan. 27, 2022, designating theUnited states, now pending, and further claims to the benefit ofpriority from Chinese Application No. 202110211159.8 with a filing dateof Feb. 25, 2021. The content of the aforementioned applications,including any intervening amendments thereto, are incorporated herein byreference.

TECHNICAL FIELD

The disclosure relates to a frustum embedded fabricated compositeprotective structure.

BACKGROUND

With the upgrading and development of weapons and equipment, as well asthe severe situation of terrorist explosion attacks, the protectionperformance of armor equipment and protective structures is facing moresevere challenges, it is urgent to develop lighter and more effectivearmor and protective structures. Ceramic materials such as Al₂O₃, B₄C,SiC, TiB₂ and AlN have the characteristics of low density, highhardness, high compressive strength, etc., which can effectivelypassivate and abrade projectiles, and can significantly improve theanti-penetration of armor. Concrete is one of the most widely used civilengineering materials, widely used in military and civil air defenseprojects, and also a very important material for nuclear containment.However, ceramics and concrete, as brittle materials with low toughnessand low tensile strength, are prone to brittle fracture and collapseunder the impact of projectiles, and anti-penetration performance ofwhich is seriously affected. When the bullet proof layer structure ofceramic or concrete is constrained by the ductile steel pipe, fiberreinforced material and other partition blocks, its ballisticperformance is obviously better than that of the bullet proof layerunder the unconstrained condition, and the smaller the diameter of thefoundation unit constrained by the partition block, the better itsanti-penetration and anti-multiple strike performance. This is becauseits radial expansion and crack propagation are limited under theconstraint, which greatly improves its strength and toughness, andsignificantly improves its anti-penetration performance.

The research shows that the anti-penetration performance of ceramicmaterials can be further improved by prestressing on the basis ofpartition block constraint. It is found from the tests that under therestraint of the lateral plate and the biaxial prestressed, the staticand dynamic strength and hardness of the ceramic target grow with theincrease of the prestress. The prestress applied to the ceramic targetcan counteract the local impact transient tensile stress of theprojectile, and effectively inhibit the initiation and propagation ofcracks in the target. Even if the ceramic interior breaks or cracksunder high-speed impact, the crack blocks are squeezed tightly, withonly cracks but no expansion, which makes the interior of the brokenceramic region have greater penetration resistance, effectivelyimproving the anti-penetration and anti-impact performance of theceramic. Although the research on anti-penetration performance ofconcrete under prestressed constraint condition is relatively rare, theprestressed constraint effect of partial block is also applicable tobrittle materials such as concrete and glass.

The mechanical extrusion method and the hot charging method are mainlyused for the prestress restraint of the partition block ceramics. Themechanical extrusion method is to push the side plate to directlyextrude the side of the ceramic plate in the inner direction of theceramic panel, and apply transverse prestress to the ceramics; the hotcharging method is to assemble the ceramic blocks and metal restraintrings with a surplus difference under high temperature, and compress theceramics to apply prestress after the overall cooling of the metal witha larger thermal expansion coefficient and faster shrinkage. Forexample, the Chinese patent application with application number201810777211.4 discloses a constrained ceramic-metal compositebulletproof armor plate and its preparation method. However, it isdifficult to apply prestress to ceramic materials by these two methods,and it is more difficult to conduct prestress restraint on brittlematerials such as concrete and glass with poor heat resistance bypartial blocks. The Chinese patent application with application number202010591444.2 discloses a prestressed restraint block for compositearmor structure, which is wedged by matching the frustum filling body ofthe frustum with the frustum surface of the restraint ring, so that itis easier to apply radial prestress to the filling body, and biaxialprestress can be applied to ceramic, concrete, glass and other fillingmaterials at room temperature. If the third direction prestress isapplied to the restraint block on the basis of biaxial prestress, itsballistic performance will be greatly improved.

At present, prestressed concrete is widely used in large-spanstructures, and the commonly used prestress methods are pre-tensioningmethod and post-tensioning method, both of which apply prestress throughthe rebound of pretensioned reinforcement bar. Pre-tensioning method isapplicable to small and medium-sized components, which is relativelyeasy to apply prestress to small size concrete components, but it isdifficult to achieve confining prestress constraint on multiple smallsize component composite structures. Once the prestress is applied, theprestress cannot be adjusted again. Post-tensioning method is generallyused for large components, prestress may have a counteraction whenprestressed concrete is prone to collapse and splash in a large areaunder strong dynamic load of explosion or penetration. When applied tosmall size components, it is difficult to arrange the prestressedreinforcement bar, even if the prestressed reinforcement bar is wellarranged, the short reinforcement bar would lead to a large loss ofprestress. So it is difficult to control the prestress applied to thematerials. In addition to the pre-tensioning method and post-tensioningmethod, the expansion concrete can also produce prestress inside thematerial, and the magnitude of prestress caused by expansion concrete is0.17 MPa^(˜)3.45 MPa, due to the small prestress, it is mostly used forshrinkage compensation and self-stressing concrete, and generally notused as the prestress loading mode of concrete structures. Therefore, itis difficult to achieve the partial block prestress constraint by usingthe above prestress methods. At present, large doors, slabs, walls andother protective structures are mostly reinforced concrete or steelplate-concrete structures, and there is no concrete protective structuresuch as doors, slabs, walls and other concrete protective structureswith fabricated partition prestressed restraints.

SUMMARY

The disclosure solves the deficiencies of the prior art and provides afrustum embedded fabricated composite protective structure. Thedisclosure presses the infill blocks made of concrete, ceramics, glassand other materials into the hoops made of metal or fiber reinforcedpolymer or into each lattice hoop of the restraint frame. The hoopapplies two-dimensional or three-dimensional prestress to the infillblocks through the taper wedge method to form a partition blockprestress restraint and fabricated composite protective structure.

The disclosure adopts the following technical solutions:

A frustum embedded fabricated composite protective structure, includinga restraint frame, a back plate, an infill block and a buffer block,wherein the restraint frame is provided with a plurality of throughholes matching the size of the infill block to form mounting holes, therestraint frame is arranged on the back plate, the infill block is in afrustum shape, the buffer block is arranged on the smaller end of theinfill block, and the buffer block and the infill blocks are installedin the mounting holes of the restraint frame, and the infill block iswedged into the mounting hole of the restraint frame through a wedgesurface mating, while the buffer block is constrained at a bottom of themounting hole, and the infill block, and the buffer block and the backplate are fastened by fasteners.

In some embodiments, the restraint frame is formed by connecting theouter walls of a plurality of hoops, and the inner cavity of each of theplurality of hoops forms the mounting hole.

In some embodiments, the shape of infill block is a frustum of hexagonalpyramid, a frustum of regular pyramid, a frustum of cone or a frustum ofregular twelve pyramid. When the infill block is the frustum ofhexagonal pyramid, the restraint frame is connected by a plurality ofhexagonal hoops to form a honeycomb type.

In some embodiments, a cover plate is arranged on an opening side of therestraint frame, the restraint frame is clamped between the back plateand the cover plate; the fasteners comprise bolts and nuts, and at leastone bolt hole penetrates through the cover plate, the infill block, thebuffer block and the back plate; and the cover plate and the back platefixedly connect the infill block and the buffer block with each otherthrough the bolts and the nuts. With the above structure, the prestressbetween the back plate and the infill block and the prestress along thedirection perpendicular to the flat top of the infill block can beadjusted by the tightness of the bolts. The strength of the infill blockincreases with the increase of the prestress.

In some embodiments, the gap between the hoops is filled with a gapfiller. The gap filler may be used materials such as concrete or fiberreinforced polymer. On the one hand, the gap filler can connect adjacenthoops, and on the other hand, the integrity of the restrained frame canbe improved.

In some embodiments, an opening side of the restraint frame is providedwith a cover plate, the restraint frame is clamped between the backplate and the cover plate; the fasteners comprise bolts and nuts, and atleast one bolt hole penetrates through the cover plate, the gap filler,and the back plate; the cover plate, the gap filler and the back plateare fixedly connected with each other through the bolts and the nuts.

In some embodiments, the fasteners comprise bolts and nuts, at least oneof the bolts is embedded in the infill block, and a corresponding bolthole is provided to penetrate the buffer block and the back plate, thebolt passes through the bolt hole reserved in the back plate, and theinfill block, the buffer block and the back plate are fixedly connectedwith each other.

In some embodiments, the infill block is a single-layer or multi-layerstructure. The infill block is composed of one or more materials fromceramics, concrete and glass, and an outer surface of the infill blockis wrapped with fiber reinforced polymer or metal plate to form asurface reinforcement layer. As the frustum of ceramic, concrete andother materials is prone to local damage in the corner area of theinfill block in contact with the hoops during the process of pushinginto the hoops, fiber reinforced polymer can be wrapped on the surfaceof the infill block or metal plate materials can be provided for surfacereinforcement before the infill block is pushed into the hoops toprevent damage or delamination due to excessive local stress during thepushing process. An opening side of the restraint frame is provided witha cover plate, the restraint frame is clamped between the back plate andthe cover plate; the fasteners comprise bolts and nuts, and at least onebolt hole is provided to penetrate edge areas of the cover plate and theback plate; the cover plate and the back plate are fixedly connectedwith each other through the bolts and the nuts, and the cover plate andthe infill block are bonded by a binder.

In some embodiments, inclined angles of the infill block and the hoopmatching with the infill block ranges from 0.5° to 10°. Preferably 1° to4°, the inclined angle here is referred to the included angle betweenthe vertical direction and the generatrix of the outer wall of thefrustum of the infill block and the generatrix of the inner wall of thehoop, or the included angle between the vertical direction and thepyramidal line of the outer wall of the frustum and the pyramidal lineof the inner wall of the hoop.

In some embodiments, a thickness of the infill block decreases from thecenter of the restrained frame to the periphery in a parabola or linearform, and a thickness of the buffer block increases correspondingly withthe decrease of the thickness of the infill block, so that a totalthickness of the infill block and the buffer block in each mounting holematches a depth of the mounting hole. By changing the thickness of theinfill block, the infill block in the middle of the whole structure ofthe device is thicker than the infill blocks around. In this way, thebending moment of the structure is reduced from the mid-span region tothe surrounding area after being subjected to explosion or strongdynamic load outside, which is conducive to saving costs and improvingthe utilization rate of materials.

The Advantageous Effects of the Disclosure

Compared with the prior art, the disclosure enables the hoop restraintinfill block to have a self tightening function through the hooprestraint principle, which can greatly improve the protection effectwhen the device is used as a protective structure, and the devicepresses the infill block into the hoop in the restraint frame, which cancontrol the size of the confining prestress by controlling the pressingdepth during assembly, so as to optimize the anti-penetration andanti-explosion performance of the infill block. At the same time, thedevice can adjust the prestress between the back plate and the infillblock and the prestress along the direction perpendicular to the flattop of infill block by tightening the bolts. The strength of the infillblock increases with the increase of prestress. In the device, theinfill block can be made of concrete, ceramics or glass, and the hoopcan be made of metal or fiber reinforced polymer. Therefore, the hoopcan easily apply prestressing in the radial and vertical direction onthe infill block at room temperature, so as to restrain the crack growthof the infill block effectively, improve the anti-penetrationperformance of the whole structure, which is suitable for applyingprestressing on protective components of various sizes. The restraintframe adopts a combination of multiple hoops. When the restraint framestructure is damaged, the rapid disassembly and repair of the restraintframe can be achieved by replacing the hoops. In addition, because theinfill block is frustum shaped, the outer diameter of the bottom surfaceof the infill block and the inner diameter of the mounting hole of thehoop have greater tolerance, which can allow greater processing errors.Compared with other assembly modes, it is more environmentally friendlyand easier to achieve, and it is easier to apply prestress or adjust theprestress. Prestress of a single hoop to confine infill block hasexcellent local anti-impact performance, while the honeycomb confinedframe composed of multiple hoops has excellent integrity and bendingresistance, showing very good overall performance. As the infill blockis pushed into the hoop to form a door, plate, wall and other platestructures, the confining pressure prestress restraint can greatlyimprove the compressive strength of the infill block, correspondinglyimprove the compressive strength of the compression area of the plate,and improve the overall bending strength and bending stiffness of theplate, making the structure more excellent in resisting the overalleffect loads such as explosion impact.

To sum up, this fabricated composite protective structure is assembledby a restraint frame and multiple infill blocks. The prestress restrainteffect of partition blocks can improve the anti-penetration andanti-explosion performance of the structure, greatly reduce the damagerange of penetration or explosion, and can withstand multiple strikes.In the case that only one infill block is damaged, it is not necessaryto replace other infill blocks. It only requires to take out andreplaces the damaged infill block, which is more cost-saving thanreplacing the entire large-area infill block. In addition, when theinfill block is damaged, it can be removed from the large port of thehoop to quickly repair and replace the damaged component. In view ofthese advantages, the disclosure has broad application prospects inisland reef protection structures, aircraft hangars, missile wellcovers, ships, armed helicopters, armored vehicles, tanks and otherprotection fields.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an internal structure assembly diagram of embodiment 1 of thepresent disclosure.

FIG. 2 is an external structure diagram of embodiment 1 of the presentdisclosure.

FIG. 3 is an internal structure assembly diagram of embodiment 2 of thepresent disclosure.

FIG. 4 is an external structure diagram of embodiment 2 of the presentdisclosure.

FIG. 5 is an internal structure assembly diagram of embodiment 3 of thepresent disclosure.

FIG. 6 is the structural diagram of the restraint frame, the frustumfiller and the buffer block in embodiment 3 of the present disclosure.

FIG. 7 is an internal structure assembly diagram of embodiment 4 of thepresent disclosure.

FIG. 8 is an external structure diagram of embodiment 4 of the presentdisclosure.

FIG. 9 is an internal structure assembly diagram of embodiment 5 of thepresent disclosure.

FIG. 10 is an external structure diagram of embodiment 5 of the presentdisclosure.

FIG. 11 is an internal structure assembly diagram of embodiment 6 of thepresent disclosure.

FIG. 12 is an external structure diagram of embodiment 6 of the presentdisclosure.

FIG. 13 is an internal structure assembly diagram of embodiment 7 of thepresent disclosure.

FIG. 14 is an external structure diagram of embodiment 7 of the presentdisclosure.

Numbers marked in the figures: 1. infill block; 11. bolt holes; 2.restraint frame; 3. buffer block; 4. cover plate; 5. back plate; 6.bolts; 7. gap filler; 8. bolt anchor; 9. nut.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Several embodiments of the disclosure are described in detail belowaccording to the drawings.

Embodiment 1

In this embodiment, the infill block 1 is an infill block 1 in the shapeof frustum of a hexagonal pyramid. The restraint frame 2 is a honeycombtype restraint frame 2, the honeycomb type restraint frame 2 is composedof multiple hoops in the shape of frustum of a hexagonal pyramid, andthe infill block 1 in the shape of frustum of a hexagonal pyramid andthe restraint frame 2 constitute the device shown in FIG. 1 . The hoopis anchored on the back plate 5 by bolts or connected with the backplate 5 by welding. At the bottom of mounting hole of each hoop, abuffer block 3 made of elastic and buffering materials such as foamaluminum and foam polymer is filled, and then the infill block 1 ispressed into the hoop in the restraint frame 2, and the lateralconfining prestress of infill block 1 is controlled by controlling thepressing depth, such that the anti-penetration and anti-explosionperformance of infill block 1 is optimized.

The cover plate 4 is covered on the restraint frame after all infillblocks 1 are pressed into the restraint frame 2. The reserved bolt holes11 on the back plate 5, the buffer block 3, the infill block 1 and thecover plate 4 are used to combine the components of the back plate 5,the restraint frame 2 and the cover plate 4 into an integral structurethrough bolts, as shown in FIG. 2 . By adjusting the tightness of thebolts, the prestress in the direction perpendicular to the flat top ofinfill block 1 can be adjusted, so that the three-dimensional prestresscan be achieved for infill block 1, and the ballistic and impactresistance of the infill block 1 can be enhanced. When the structure isdamaged, it can be quickly disassembled and repaired.

Embodiment 2

As shown in FIG. 3 , the difference between this embodiment andEmbodiment 1 lies in that in this embodiment, the infill block 1 is aninfill block 1 in the shape of frustum of a cone, and the hoop of therestraint frame 2 is a hoop in the shape of frustum of a cone. When theinfill block 1 in the shape of frustum of a cone is assembled, there isa gap between the hoops, so the gap filler 7 should be filled betweenthe hoops. The gap filler 7 may be materials such as concrete, fiberreinforced polymer or foam aluminum and other materials, and theintegral structure assembled by the back plate 5, the cover plate 4, therestraint frame 2 and the infill block 1 in the shape of frustum of acone is shown in FIG. 4 .

Embodiment 3

As shown in FIG. 5 and FIG. 6 , this difference between Embodiment 1 andthis embodiment lies in that the infill block 1 in this embodiment is aninfill block 1 in the shape of frustum of a regular pyramid. In order tofit the side surface of the frustum of a regular pyramid, the hoop isformed by connecting four wedge-shaped side plates with linearly varyingthickness or by using equal-thickness side plates placed according tothe inclination of the side surface of the frustum of the regularpyramid.

When this embodiment is applied to a protective door, panel or wallstructure, the boundaries around the door, panel or wall structure aregenerally constrained such that the bending moment of the overallstructure of this device generally decreases from the mid-span region tothe periphery after being subjected to strong dynamic load such asexplosion or penetration. In order to improve material utilization, thethickness of the infill block in this embodiment decreases from thecenter of the restrained frame to the periphery in a parabola or linearform, or varies according to the magnitude of the bending moment. Thethickness of the buffer block increases with the decrease of thethickness of the infill block, so that the total thickness of the infillblock and the buffer block in each mounting hole matches the depth ofthe mounting hole. The buffer block use aluminum foam, honeycombmaterial, polymer flexible material as cushioning layer to absorb energysuch as shock waves and reduce damage to people and objects behind thedoor, panel or wall. The back plate 5 is welded or bolted to therestraint frame 2. To further increase the protective effect, panelrestraint can be added by fastening the back plate 5 and panel withbolts to further apply prestress in the direction of the bolt axis tothe infill block 1 to achieve three-dimensional prestress restraint andincrease the protective performance.

Embodiment 4

In this embodiment, the infill block is an infill block 1 in the shapeof frustum of a regular dodecagonal pyramid, the restraint frame 2 takesthe hoop in the shape of frustum of a regular dodecagonal pyramid as thebasic unit, and a plurality of the infill blocks 1 in the shape offrustum of a regular dodecagonal pyramid and the restraint frame 2 areassembled into a hexagonal composite protective structure, as shown inFIG. 7 . The hoop is anchored on the back plate 5 by bolts, or connectedto the back plate 5 by welding or bonding. Buffer blocks 3 such as foamaluminum and foam polymer are filled at the bottom of the mounting holeof each hoop, and then the infill block 1 is pressed into the hoop inthe restraint frame 2. The size of lateral confining prestress of theinfill block 1 is controlled by controlling the pressing depth, so thatthe anti-penetration and anti-explosion performance of infill block 1 isoptimal. Concrete, fiber reinforced polymer or foam aluminum and othermaterials are used as gap filler 7 for filling gaps between the hoops inthe shape of frustum of a regular dodecagonal pyramid. The integralstructure assembled by the back plate 5, the cover plate 4, the bufferblock 3, the restraint frame 2 and the infill block 1 in the shape offrustum of a regular dodecagonal pyramid is shown in FIG. 8 . Theprestress in the direction perpendicular to the flat top of infill block1 can be adjusted with the bolt tightness.

Embodiment 5

As shown in FIG. 9 , the difference between this embodiment andEmbodiment 1 is that in this embodiment, the overall structure is ahexagonal composite protective structure assembled by a plurality ofinfill blocks 1 in the shape of frustum of regular hexagonal pyramid anda restraint frame 2. The overall structure is shown in FIG. 10 .

Embodiment 6

As shown in FIG. 11 , this embodiment is based on Embodiment 5. Thedifference between the two is that bolt holes 11 are not set on infillblock 1 in the shape of frustum of hexagonal pyramid and the bufferblock 3 in this embodiment, and bolt holes are only set at the edges ofthe cover plate 4 and the back plate 5. The cover plate 4 and the backplate 5 are bonded with the infill block 1 by the binder, and thesurrounding of the structure is connected with bolts. The embodiment isapplicable to small protective structural members, such as small ceramiccomposite armor plate. The overall structure is shown in FIG. 12 .

Embodiment 7

As shown in FIG. 13 , the difference between this embodiment andEmbodiment 5 is that the structure in this embodiment is not providedwith a cover plate 4, but is anchored with the back plate 5 by embeddedbolt anchor 8 in the infill block 1. The size of lateral confiningprestress of infill block 1 is controlled by the fastening degree ofembedded bolt anchor 8 and the back plate 5, and the overall structureis shown in FIG. 14 . In this embodiment, the outer surface of theinfill block 1 can be wrapped with fiber reinforced polymer or providedwith metal plate materials for surface reinforcement, so the cover plate4 may not be provided. In this embodiment, in order to enhance thestructural integrity and the controllability of lateral confiningprestress, more bolt anchors 8 can be embedded in the infill block 1.

In the above embodiments 1-5, each infill block 1 only reserves one bolthole 11. However, in order to enhance the structural integrity andincrease the size of the third direction prestress, more bolt holes 11can be reserved on each infill block 1, or at least one bolt anchor 8can be embedded in the infill block 1 to connect the back plate 5.

The shape of the fabricated composite protective structure in the aboveseven embodiments is not limited to rectangular or hexagonal shapes,such as doors, panels, walls, etc., but also can be assembled intocircular shapes, such as missile well covers, or special-shaped shapes.The protective structure panel can also be assembled into cylindrical,spherical and other curved shapes. The shape of the restraint frame 2and the number of infill blocks 1 are determined according to the actualworking conditions. Except for Embodiment 3, the thickness of the infillblock 1 in other embodiments can also be reduced parabola or linear fromthe mid-span region to the periphery according to the possible bendingmoment distribution.

What is claimed is:
 1. A frustum embedded fabricated compositeprotective structure, comprising a restraint frame, a back plate, aninfill block and a buffer block, wherein the restraint frame is arrangedon the back plate, the infill block is in a frustum shape, the bufferblock is arranged on the smaller end of the infill block, and therestraint frame is provided with a plurality of through holes matching asize of the infill block to form mounting holes, the buffer block andthe infill blocks are installed in the mounting holes of the restraintframe, and the infill block is wedged into the mounting hole of therestraint frame through a wedge surface mating, while the buffer blockis constrained at a bottom of the mounting hole, and the infill block,the buffer block and the back plate are fastened by fasteners.
 2. Thefrustum embedded fabricated composite protective structure according toclaim 1, wherein the restraint frame is formed by connecting a pluralityof hoops matching a shape of the infill block, and an inner cavity ofeach of the plurality of hoops forms the mounting hole.
 3. The frustumembedded fabricated composite protective structure according to claim 2,wherein the shape of infill block is a frustum of hexagonal pyramid, afrustum of regular pyramid, a frustum of cone or a frustum of regulartwelve pyramid.
 4. The frustum embedded fabricated composite protectivestructure according to claim 2, wherein a cover plate is arranged on anopening side of the restraint frame, the restraint frame is clampedbetween the back plate and the cover plate; the fasteners comprise boltsand nuts, and at least one bolt hole penetrates through the cover plate,the infill block, the buffer block and the back plate; the cover plateand the back plate fixedly connect the infill block and the buffer blockwith each other through the bolts and the nuts.
 5. The frustum embeddedfabricated composite protective structure according to claim 2, whereinthe gaps between the hoops are filled with a gap filler.
 6. The frustumembedded fabricated composite protective structure according to claim 5,wherein an opening side of the restraint frame is provided with a coverplate, the restraint frame is clamped between the back plate and thecover plate; the fasteners comprise bolts and nuts, and at least onebolt hole penetrates through the cover plate, the gap filler, and theback plate; the cover plate, the gap filler and the back plate arefixedly connected with each other through the bolts and the nuts.
 7. Thefrustum embedded fabricated composite protective structure according toclaim 1, wherein the fasteners comprise bolts and nuts, at least one ofthe bolts is embedded in the infill block, and a corresponding bolt holeis provided to penetrate the buffer block and the back plate, the boltpasses through the bolt hole reserved in the back plate, and the infillblock, the buffer block and the back plate are fixedly connected witheach other.
 8. The frustum embedded fabricated composite protectivestructure according to claim 2, wherein an opening side of the restraintframe is provided with a cover plate, the restraint frame 2 is clampedbetween the back plate and the cover plate; the fasteners comprise boltsand nuts, and at least one bolt hole is provided to penetrate edge areasof the cover plate 4 and the back plate 5; the cover plate 4 and theback plate 5 are fixedly connected with each other through the bolts andthe nuts, and the cover plate 4 and the infill block 1 are bonded by abinder.
 9. The frustum embedded fabricated composite protectivestructure according to claim 1, wherein the infill block is asingle-layer or multi-layer structure, the infill block is composed ofone or more materials from ceramics, concrete and glass, and an outersurface of the infill block is wrapped with fiber reinforced polymer ormetal plate to form a surface reinforcement layer.
 10. The frustumembedded fabricated composite protective structure according to claim 2,wherein inclined angles of the infill block and the hoop matching withthe infill block ranges from 0.5° to 10°.
 11. The frustum embeddedfabricated composite protective structure according to claim 1, whereina thickness of the infill block decreases from a centre of therestrained frame to a periphery in a parabola or linear form, and athickness of the buffer block increases correspondingly with thedecrease of the thickness of the infill block, so that a total thicknessof the infill block and the buffer block in each mounting hole matches adepth of the mounting hole.